Extrusive Rock: An igneous rock that is created when lava erupts on the surface of earth. Intrusive Rock: An igneous rock that is created from hardened magma below the surface of earth. Porphyritic Texture: The texture of an igneous rock, where big crystals are spread behind much smaller crystals.
Outline
Characteristics of Igneous Rock
Igneous rock forms from lava or magma
Most igneous rocks are made of mineral crystals
Origin
Igneous rocks are classified according to where they formed
Extrusive: lava on earth's surface
Intrusive: magma below earth's surface
Texture
Fast-cooling creates fine grained rocks
Porphyritc forms when first magma cools slowly, then remaining magma cools fast
Mineral Composition
Lava high in silica makes light colored rocks (granite)
Lava low in silica makes dark-colored rocks (basalt)
Color varies on mineral amounts
Uses of Igneous Rocks
Many Igneous rocks are hard, dense, and durable
Granite has long history as building material
Many different countries and states used it for different things
Table of Contents
5.2 Igneous Rocks (pg. 140)
Vocabulary
Extrusive Rock: An igneous rock that is created when lava erupts on the surface of earth.
Intrusive Rock: An igneous rock that is created from hardened magma below the surface of earth.
Porphyritic Texture: The texture of an igneous rock, where big crystals are spread behind much smaller crystals.
Outline
Characteristics of Igneous Rock
- Igneous rock forms from lava or magma
- Most igneous rocks are made of mineral crystals
Origin- Igneous rocks are classified according to where they formed
- Extrusive: lava on earth's surface
- Intrusive: magma below earth's surface
Texture- Fast-cooling creates fine grained rocks
- Porphyritc forms when first magma cools slowly, then remaining magma cools fast
Mineral CompositionUses of Igneous Rocks
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